Harley Davidson Battery question

I know that quite a few of you have motorcycles. I have a 1997 Ultra Classic that I have been using lawn mower batteries in for the last few years. They only last for 1-2 years before giving up. I priced one at the dealership and is was $275.00. I ran Harley batteries before and couldn't get more than 3 years out of. Any suggestions for a decent battery that isn't so spendy?